This invention relates in general to sound transmitting devices and in particular to a new and useful ear piece for a sound producing device such as a headset.
The invention relates to an annular ear cushion comprising at least two interconnected parts, one part comprising an elastic, soft, sound permeable material, and an ear cushion associated with a supraaural headset ear piece.
When in use, ear cushions for supraaural headset ear pieces are located between the headset ear piece and the user's outer ear. It is the task of the ear cushion to make wearing a headset over the ear more pleasant, as the ear cushions of the headset ear pieces reduce the pressure exerted by the headset on the outer ear. The pressure against the outer ear is necessary for better acuostic coupling of the headset to the ear, and in many applications as close a seating of the ear cushions against the outer ears is required to achieve optimum acoustic coupling. The ear cushion is often used also to muffle disturbing resonances developing in the coupling space acting as a Helmholtz resonator.
Embodiments in common use and possible applications of ear cushions for headset ear pieces are known from AT-PS 274,918, DE-OS 26 37 336 and the technical journal Funkschau, No. 23,1978, pages 1159-61. But in these ear cushions of the state of the art the defined seating of the headset on the ear and its associated acoustic coupling to the ear is vague, and a precisely reproducible frequency response from the lowest to the medium frequencies transmitted, e.g. from 20 Hz to 2 kHz, cannot be obtained with such ear cushions in a satisfactory manner.
The DE-AS 15 37 700 also refers to the limited quality of headsets, especially at the lower frequencies. To eliminate the undefined conditions of the contact between ear piece and outer ear, the publication proposes to move the diaphragm resonance to the lower end of the transmission range and also to provide special mechanical means to prevent the auditory canal from being sealed from the air space surrounding the head and the electro-acoustic transducer. The DE-OS 22 52 189 also indicates, for a headset with an open backside, for the unequivocal reproduction of a uniform frequency response at low and medium frequencies of the range of audibility, a solution of the not unequivocal conditions present due to the ear cushion, which solution is supposed to be that there are provided in the diaphragm itself or/and in the housing part supporting the diaphragm many small holes to control the leakage from the front to the back of the diaphragm.